Drum-type venetian blinds



Oct. 29, 1968 I F. GRIESSER 3, 0

DRUM-TYPE VENBTIAN BLINDS Filed Dec. 2, 1966 5 Sheets-Sheet 1 Oct. 29, 1968 GR|EssER 3,407,863

DRUM-TYPE VENET IAN BLINDS Filed Dec. 2. 1966 r 3 Sheets-Sheet 2 l nun Oct. 29, 1968 F. GRIESSER 3,407,863

DRUM-TYPE VENETIAN BLINDS Filed Dec. 2, 1966 3 Sheets-Sheet 5 United States Patent Olfice 3,407,863 Patented Oct. 29, 1968 DRUM-TYPE VENETIAN BLINDS Friedrich Griesser, Aadorf, Thurgau, Switzerland, as siguor to Griesser A.G., Aadorf, Thurgau, Switzerland Filed Dec. 2, 1966, Ser. No. 598,655 Claims priority, application Switzerland, Dec. 3, 1965,

16,696/65; Jan. 14,1966, 479/66 11 Claims. (Cl. 160-133) ABSTRACT OF THE DISCLOSURE Venetian blinds of the type in which the slats are pivotally connected to guide tapes and draw tapes which are wound up on a drum for raising and lowering the blinds. The blind slats are also adapted to be opened and closed by turning the drum. Pivot tape mechanism is included with the drum structure which permits the slats to be quietly brought together even though the drum is rotated at maximum speed.

Background of the invention The present invention relates to Venetian blinds which are wound up on a drum. The slats are pivotally connected to guide tapes, and a beaded edge of the slats is pivotally connected to a draw tape that is secured to the drum, as is known in the art. Once the blinds are fully lowered the guide tapes stop moving, and further turning of the drum causes the slats to pivot and the blinds to open.

The longitudinal edges of the slats of such blinds generally are headed. The slats are pivotally so connected to the tapes that they overlap when closed. When the slats are pivoted to close the blinds, the lower bead of one slat will strike the surface in a front of the upper head of the next lower slat, causing a not inconsiderable noise.

In a prior attempt to reduce this noise, a strip of rubbery material, which covered the front slat surface immediately before the upper bead, was secured in the upper head of each slat. However, it was found that this expedient, with hand or motor operated blinds, did not satisfactorily deaden the noise when the blinds were closed turning the drum at a normal speed.

Summary of the invention This invention is directed to Venetian blinds that are wound up on a drum, including a series of slat members which are to be pivoted when the blinds are opened or closed, at least two guide tapes, at least two draw tapes and drum means for raising and lowering the blinds. The slats are pivotally connected to the guide tapes and draw tapes, the latter of which are secured to the drum means. The turning of the drum causes the pivotal slat members to pivot and the blinds to open. At least one pivot tape is provided for pivoting the pivotal slat members with means for connecting the pivot tape to at least the uppermost one of the slat members along the edge thereof which is uppermost when the blinds are closed. The drum means have a first larger and a second smaller winding radius with the draw tapes being wound on said first winding radius and means securing the pivot tape to the drum means for winding on the second winding radius. The pivot tape is taut when the blinds are completely lowered.

Accordingly, the drum-type Venetian blinds of this invention provide a speed ratio for winding up the blind in the pivotal range of the slats which is different from that in the raising range of the blinds such that the slats are gently and quietly closed.

An object of the invention is an arrangement for greatly reducing the noise caused by blind slats striking together, when the blinds are closed, which arrangement does not unfavorably effect installation of the blinds.

This and further objects of the invention will be apparent from the following detailed description of two embodiments, read in conjunction with the figures of the accompanying drawings, wherein:

FIGURE 1 is a front view of a part of the first embodiment of the invention, blinds open;

FIGURE 2 is a side view of the same embodiment, showing the upper portion of the blinds;

FIGURE 3 is a rear view of the same embodiment, showing a part of the upper portion of the blinds;

FIGURE 4 is a rear view of a second embodiment of the invention, showing a part of the blinds completely lowered;

FIGURE 5 is a side of the second embodiment blinds open; and

FIGURE 6 is a side view of the second embodiment, blinds closed.

Referring to the embodiment of FIGURES 1-3, the blinds have a series of slightly transversely bent slats 1 which may be formed of sheet metal. Each slat incorporates an upper outwardly beaded edge 2 and a lower inwardly beaded edge 3, as seen when the blinds are closed and from the outside. The rear face of each slat is pivotally connected to two steel guide tapes 4, FIGURE 1, respectively neighboring the two ends of the slats. For this purpose a pin 5 is provided which is secured to a respective slat by a socket (not referenced) at each end of the slat. Each pin turns in a corresponding eye 6 made of sheet metal, and the two feet of which are spot welded or riveted to the tape 4.

Each of the two tapes 4 runs in a respective rail 7. An end rail (not shown) is mounted on the lower ends of the tapes 4.

As shown in FIGURE 3, the upper end of each rail 7 terminates in a somewhat expanded portion that is connected to the narrower length of the rail by a shoulder (not referenced) that serves as a stop for a small block 15 mounted on the upper ends of the tapes 4.

The wind-up drum 8 is shown in FIGURES 2 and 3. One end of the drum mounts a drive wheel (not shown) carrying a toothed gear meshing with gearing operated by a crank.

T-wo steel draw tapes 9 are secured to the drum 8 by a metal strap 10. With the exception of the four upper most slats (see FIG. 3), all of the slats 1 are pivotally secured to the tapes 9 along their beaded edges 2. For this purpose each slat incorporates two cutouts located immediately next to the edge 2 and aligned with respective ones of the tapes 9. An eye 11, which may be made of a suitable synthetic plastic and is somewhat narrower than the respective cutout, is secured to each tape 9 for each of the slats pivotally mounted on the tapes 9. The head of an edge 2 thus acts as a pin in the two edges 11.

The four uppermost slats are connected together by one or more tapes to form a portion of the blinds that cannot be pivoted and is always closed. The draw tapes 9 are connected to each of the four uppermost slats.

A pivot tape 12, which may be of steel, is connected to the uppermost pivotal slat 1 near an end of the latter. This tape is secured to a portion 14 of the drum 8 which has a smaller diameter. The tape 12 can be wound up on the portion 14, and winds around it in the same direction as do the draw tapes 9 around their portion of the drum. The lower end of the pivot tape 12 makes a closed loop (FIG. 1) which passes through a cutout in the uppermost pivotal slat 1 which is somewhat wider than the tape 12, to form a connection between the slat and the tape that permits the slat to pivot. If the blinds are wide, two such tapes 12 can be provided, connected near each 3 end of the slat. In this case, the drum 8 will have a portion 14- for each tape 12.

The uppermost pivotal slat has a thicker, stronger cross section than the other slats.

As is apparent from FIGURE 3, the tape arrangement is such that over the pivotal range of the slats, the pivot tape 12 is taut and the draw tapes 9' are slack, so that when the slats are pivoted from their open to their closed position, by turning the drum 8 clockwise (as seen in FIG. 3), the slats are pivoted solely by action of the pivot tape 12. Inasmuch as the diameter of the drum portion 14 is appreciably smaller than that of the rest of the drum 8, the tape 12 is rolled up much more slowly than the draw tapes 9. The winding radius for the tape 12 is smaller than for the tapes 9. The diameter of the drum portion 14 can be such with respect to the rest of the drum that the slats are gently and quietly closed even when the drum is rotated rapidly.

In the embodiment of FIGURES 4-6 the blinds again have a series of slats 21, of sheet metal, for example, having a slighly curved cross section, and incorporating upper and lower beaded edges 22 and 23, as seen in the closed position of the slats, FIGURE 4. Each of the slats is pivotally connected to two steel guide tapes 24-, respectively neighboring the slat ends. For this purpose a pin 25 is secured by a plate (not referenced) on the rear slat face at each end of a slat. Each pin turns in a respective eye (not shown) made of sheet metal, and the two feet of which are spot welded or riveted to a respective tape 24.

Each of the two tapes 24 runs in a respective rail 26. An end cross member 27 is connected to the lowermost slat 21 and also runs in the rails 26.

As in the first embodiment, the upper end of each rail 27 terminates in a somewhat expanded portion (FIGS. 5 and 6) that is connected to the narrower length of the rail by a shoulder 40 that serves as a stop for a small block 28 mounted on each of the upper ends of the tapes 24.

The wind-up drum 29 at one end mounts a drive wheel (not shown) carrying a toothed gear meshing with gearing operated by a crank. Two draw tapes 30 respectively located near the one and the other ends of the slats and a central pivot tape 31 are connected to the drum by respective straps 32 and 33. The slats 21 are pivotally connected by their beaded edge 22 to the tapes 30 and 31. For this purpose each slat incorporates three cutouts spaced along its beaded edge 22 and aligned with an eye 37 mounted on one of the tapes 30 and 31. The eye may be made of a suitable synthetic plastic and is somewhat narrower than the cutout through which it passes. The beaded edges 22 thus acts as pins pivoting in the eyes 37 when the slats are turned. The tapes 3 (land 31 are composed of two sections: an upper length made of fabric secured to the drum 29 and connected at 34 to a lower length made of steel running along the slats.

As shown in FIGURE 4, the wind-up drum 29 has two right-circular cylindrical end portions of normal diameter to which the draw tapes 30 are connected and a central right-circular cylindrical portion 36 of reduced diameter to which the pivot tape 31 is connected. The central portion 36, as best seen in FIGURES 5 and 6, is eccentrically located with respect to the axis of the rest of the drum 29. The arrangement is such that when the blinds are completely lowered and closed, as shown in FIGURE 6, the plane defined by the axis of the central portion 36 and the axis 38 of the rest of the drum 29 is approximately perpendicular to the portion of the tape 31 extending from the central drum portion 36.

The tapes 30 and 31 are so arranged, as seen in FIG- URE 5, that at least over the pivotal range of the slats the draw tapes 30 are slack and the tape 31 is taut, so that when the slats are pivoted from their open to their closed position, by turning the drum 29 clockwise (as seen in FIGURE 5), the slats are pivoted solely by action of the pivot tape 31. Since the distance between the axis 38 of the rest of drum 29 and that part 39 of the surface of the central drum portion 36 where the tape 31 begins to wind around the central portion is appreciably smaller than the diameter of the rest of the drum, the tape 31 is wound up much more slowly than the draw tapes 30, over the pivotal range of the slats. Moreover, as the slats close, the tape 31 is mound up ever more slowly, because this distance continuously decreases. This distance is also called the winding radius. The rate at which the tape 31 is wound up can be so chosen that the blinds are gently and quietly closed, even when the drum is turned at maximum speed.

The central drum portion 36 may take other forms. The portion, for example, may be elliptical, or some other similar shape, in cross section. The shape of the central drum portion in cross section is such that it has the desired eifect over the pivotal range of the slats. The shape preferably results in the distance between the surface part 39 and the axis 38 of the rest of the drum being smallest just before the blinds are completely closed. As a result, the dilference in the rates at which the draw tapes 30, on the one hand, and the tape 31, on the other, are unwound becomes progressively smaller when the blinds are opened. This difference is a maximum just before the blinds completely close and a minimum just before the blinds completely open.

Advantageously, the surface of the central drum portion 36 upon which the pivot tape 31 is wound, at the point thereof where the tape 12 begins to wind around the surface when the blinds are about to completely close, may pass through the axis of rotation 38 of the rest of the drum 29. This assures that the slats 21 will be brought almost to a standstill just before they completely close.

In the embodiment of FIGURES 4-6 several spaced pivot tapes 31 may be employed connected to a common central drum portion 36; and, with very wide blinds, several drum portions 36 of reduced diameter, spaced along the length of drum, may be advantageous.

The invention is not to be construed as limited to the particular forms disclosed herein, since these are to be regarded as illustrative rather than restrictive.

I claim:

1. Venetian blinds that are wound up on a drum, including a series of slat members at least some of which are to be pivoted when the blinds are opened or closed, at least two guide tapes, drum means for raising and lowering the blinds, means pivotally connecting at least those slats which are to be pivoted to said guide tapes, at least two draw tapes, means securing said draw tapes to said drum means, and means pivotally connecting each slat member along the edge thereof which is uppermost when the blinds are closed to each said draw tape, said guide tapes remaining stationary when the blinds are completely lowered and further turning of said drum causing the pivotal slat members to pivot and the blinds to open:

the improvement consisting of at least one pivot tape for pivoting the pivotal slat members, means for connecting said pivot tape to at least the uppermost one of the pivotal slat members along the edge thereof which is uppermost when the blinds are closed, said drum means having a first larger and a second smaller winding radius, said draw tapes being wound on said first winding radius, mean securing said pivot tape to said drum means for winding on said second winding radius, said pivot tape being taut when the blinds are completely lowered.

2. The Venetian blinds as set forth in claim 1, wherein said draw tapes are slack and said pivot tape is taut when the blinds are completely lowered for closing.

3. The Venetian blinds as set forth in claim 1, including means for pivotally connecting each of the slat members of said series to said pivot tape.

4. The Venetian blinds as set forth in claim 1, including first and second winding surfaces, as part of said drum means, associated respectively with said first and second winding radii, each said first and second surfaces defining a center of rotation, and the center of rotation of said second surface being eccentric with respect to that of said first surface.

5. The Venetian blinds as set forth in claim 4, wherein said second winding surface, at the point thereof where said pivot tape begins to wind around said second winding surface when the blinds have just at least substantially completely closed, passes through said center of rotation of said first surface.

6. The Venetian blinds as set forth in claim 5, wherein said second winding radius decreases as the blind are closed.

7. The Venetian blinds as set forth in claim 6, wherein said second winding radius is a minimum just before the blinds are completely closed.

8. The Venetian blinds as set forth in claim 5, wherein 6 said second winding surface defines a right-circular cylinder.

9. The Venetian blinds as set forth in claim 6, wherein said second winding surface, at least over the area thereof used when pivoting the pivotal slats to open and close the blinds defines at least part of an ellipse.

10. The Venetian blinds as set forth in claim 7, wherein said second surface does not project beyond said first surface.

11. The Venetian blinds as set forth in claim 9, wherein said second surface does not project beyond said first surface.

References Cited UNITED STATES PATENTS PETER M. CAUN, Primary Examiner. 

